[llvm-branch-commits] [lld] r371034 - Update ReleaseNotes for lld 9.0.

Rui Ueyama via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Thu Sep 5 02:00:16 PDT 2019 

Author: ruiu
Date: Thu Sep  5 02:00:16 2019
New Revision: 371034

URL: http://llvm.org/viewvc/llvm-project?rev=371034&view=rev
Log:
Update ReleaseNotes for lld 9.0.

Modified:
    lld/branches/release_90/docs/ReleaseNotes.rst

Modified: lld/branches/release_90/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/docs/ReleaseNotes.rst?rev=371034&r1=371033&r2=371034&view=diff
==============================================================================
--- lld/branches/release_90/docs/ReleaseNotes.rst (original)
+++ lld/branches/release_90/docs/ReleaseNotes.rst Thu Sep  5 02:00:16 2019
@@ -8,10 +8,12 @@ lld 9.0.0 Release Notes
 Introduction
 ============
 
-This document contains the release notes for the lld linker, release 9.0.0.
-Here we describe the status of lld, including major improvements
-from the previous release. All lld releases may be downloaded
-from the `LLVM releases web site <https://llvm.org/releases/>`_.
+lld is a high-performance linker that supports ELF (Unix), COFF
+(Windows), Mach-O (macOS), MinGW and WebAssembly. lld is
+command-line-compatible with GNU linkers and Microsoft link.exe and is
+significantly faster than the system default linkers.
+
+lld 9.0 has lots of feature improvements and bug fixes.
 
 Non-comprehensive list of changes in this release
 =================================================
@@ -22,52 +24,189 @@ ELF Improvements
 * ld.lld now has typo suggestions for flags:
   ``$ ld.lld --call-shared`` now prints
   ``unknown argument '--call-shared', did you mean '--call_shared'``.
+  (`r361518 <https://reviews.llvm.org/rL361518>`_)
+
+* ``--allow-shlib-undefined`` and ``--no-allow-shlib-undefined``
+  options are added. ``--no-allow-shlib-undefined`` is the default for
+  executables.
+  (`r352826 <https://reviews.llvm.org/rL352826>`_)
+
+* ``-nmagic`` and ``-omagic`` options are fully supported.
+  (`r360593 <https://reviews.llvm.org/rL360593>`_)
+
+* Segment layout has changed. PT_GNU_RELRO, which was previously
+  placed in the middle of readable/writable PT_LOAD segments, is now
+  placed at the beginning of them. This change permits lld-produced
+  ELF files to be read correctly by GNU strip older than 2.31, which
+  has a bug to discard a PT_GNU_RELRO in the former layout.
+
+* ``-z common-page-size`` is supported.
+  (`r360593 <https://reviews.llvm.org/rL360593>`_)
+
+* Diagnostics messages have improved. A new flag ``--vs-diagnostics``
+  alters the format of diagnostic output to enable source hyperlinks
+  in Microsoft Visual Studio IDE.
+
+* Linker script compatibility with GNU BFD linker has generally improved.
+
+* The clang ``--dependent-library`` form of autolinking is supported.
+
+  This feature is added to implement the Windows-style autolinking for
+  Unix. On Unix, in order to use a library, you usually have to
+  include a header file provided by the library and then explicitly
+  link the library with the linker ``-l`` option. On Windows, header
+  files usually contain pragmas that list needed libraries. Compilers
+  copies that information to object files, so that linkers can
+  automatically link needed libraries. ``--dependent-library`` is
+  added for implementing that Windows semantics on Unix.
+  (`r360984 <https://reviews.llvm.org/rL360984>`_)
+
+* AArch64 BTI and PAC are supported.
+  (`r362793 <https://reviews.llvm.org/rL362793>`_)
 
 * lld now supports replacing ``JAL`` with ``JALX`` instructions in case
-  of MIPS - microMIPS cross-mode jumps.
+  of MIPS ↔ microMIPS cross-mode jumps.
+  (`r354311 <https://reviews.llvm.org/rL354311>`_)
 
 * lld now creates LA25 thunks for MIPS R6 code.
+  (`r354312 <https://reviews.llvm.org/rL354312>`_)
 
 * Put MIPS-specific .reginfo, .MIPS.options, and .MIPS.abiflags sections
   into corresponding PT_MIPS_REGINFO, PT_MIPS_OPTIONS, and PT_MIPS_ABIFLAGS
   segments.
 
+* The quality of RISC-V and PowerPC ports have greatly improved. Many
+  applications can now be linked by lld. PowerPC64 is now almost
+  production ready.
+
+* The Linux kernel for arm32_7, arm64, ppc64le and x86_64 can now be
+  linked by lld.
+
+* x86-64 TLSDESC is supported.
+  (`r361911 <https://reviews.llvm.org/rL361911>`_,
+  `r362078 <https://reviews.llvm.org/rL362078>`_)
+
+* DF_STATIC_TLS flag is set for i386 and x86-64 when needed.
+  (`r353293 <https://reviews.llvm.org/rL353293>`_,
+  `r353378 <https://reviews.llvm.org/rL353378>`_)
+
+* The experimental partitioning feature is added to allow a program to
+  be split into multiple pieces.
+
+  The feature allows you semi-automatically split a single program
+  into multiple ELF files called "partitions". Since all partitions
+  share the same memory address space and don't use PLT/GOT, split
+  programs run as fast as regular programs.
+
+  With the mechanism, you can start a program only with a "main"
+  partition and load remaining partitions on-demand. For example, you
+  can split a web browser into a main partition and a PDF reader
+  sub-partition and load the PDF reader partition only when a user
+  tries to open a PDF file.
+
+  See https://lld.llvm.org/Partitions.html for more information.
+
+* If "-" is given as an output filename, lld write the final result
+  to the standard output. Previously, it created a file "-" in the
+  current directory.
+  (`r351852 <https://reviews.llvm.org/rL351852>`_)
+
+* ``-z ifunc-noplt`` option is added to reduce IFunc function call
+  overhead in a freestanding environment such as the OS kernel.
+
+  Functions resolved by the IFunc mechanism are usually dispatched via
+  PLT and thus slower than regular functions because of the cost of
+  indirection. With ``-z ifunc-noplt``, you can eliminate it by doing
+  text relocations at load-time. You need a special loader to utilize
+  this feature. This feature is added for the FreeBSD kernel but can
+  be used by any operating systems.
+  (`r360685 <https://reviews.llvm.org/rL360685>`_)
+
+* ``--undefined-glob`` option is added. The new option is an extension
+  to ``--undefined`` to take a glob pattern instead of a single symbol
+  name.
+  (`r363396 <https://reviews.llvm.org/rL363396>`_)
+
+
 COFF Improvements
 -----------------
 
 * Like the ELF driver, lld-link now has typo suggestions for flags.
+  (`r361518 <https://reviews.llvm.org/rL361518>`_)
 
-* lld-link now correctly reports duplicate symbol errors for obj files
-  that were compiled with /Gy.
-
-* lld-link now correctly reports duplicate symbol errors when several res
-  input files define resources with the same type, name, and language.
-  This can be demoted to a warning using ``/force:multipleres``.
-
-* lld-link now rejects more than one resource obj input files, matching
-  link.exe. Previously, lld-link would silently ignore all but one.
-  If you hit this: Don't pass resource obj files to the linker, instead pass
-  res files to the linker directly. Don't put res files in static libraries,
-  pass them on the command line.
+* lld-link now correctly reports duplicate symbol errors for object
+  files that were compiled with ``/Gy``.
+  (`r352590 <https://reviews.llvm.org/rL352590>`_)
+
+* lld-link now correctly reports duplicate symbol errors when several
+  resource (.res) input files define resources with the same type,
+  name and language.  This can be demoted to a warning using
+  ``/force:multipleres``.
+  (`r359829 <https://reviews.llvm.org/rL359829>`_)
+
+* lld-link now rejects more than one resource object input files,
+  matching link.exe. Previously, lld-link would silently ignore all
+  but one.  If you hit this: Don't pass resource object files to the
+  linker, instead pass res files to the linker directly. Don't put
+  resource files in static libraries, pass them on the command line.
+  (`r359749 <https://reviews.llvm.org/rL359749>`_)
 
 * Having more than two ``/natvis:`` now works correctly; it used to not
   work for larger binaries before.
+  (`r327895 <https://reviews.llvm.org/rL327895>`_)
 
 * Undefined symbols are now printed only in demangled form. Pass
   ``/demangle:no`` to see raw symbol names instead.
-
-* The following flags have been added: ``/functionpadmin``, ``/swaprun:``,
-  ``/threads:no``
+  (`r355878 <https://reviews.llvm.org/rL355878>`_)
 
 * Several speed and memory usage improvements.
 
-* Range extension thunks are now created for ARM64, if needed
+* Range extension thunks are now created for ARM64, if needed.
 
 * lld-link now supports resource object files created by GNU windres and
-  MS cvtres, not only llvm-cvtres
+  MS cvtres, not only llvm-cvtres.
 
 * The generated thunks for delayimports now share the majority of code
-  among thunks, significantly reducing the overhead of using delayimport
+  among thunks, significantly reducing the overhead of using delayimport.
+  (`r365823 <https://reviews.llvm.org/rL365823>`_)
+
+* ``IMAGE_REL_ARM{,64}_REL32`` relocations are supported.
+  (`r352325 <https://reviews.llvm.org/rL352325>`_)
+
+* Range extension thunks for AArch64 are now supported, so lld can
+  create large executables for Windows/ARM64.
+  (`r352929 <https://reviews.llvm.org/rL352929>`_)
+
+* The following flags have been added:
+  ``/functionpadmin`` (`r354716 <https://reviews.llvm.org/rL354716>`_),
+  ``/swaprun:`` (`r359192 <https://reviews.llvm.org/rL359192>`_),
+  ``/threads:no`` (`r355029 <https://reviews.llvm.org/rL355029>`_),
+  ``/filealign`` (`r361634 <https://reviews.llvm.org/rL361634>`_)
+
+WebAssembly Improvements
+------------------------
+
+* Imports from custom module names are supported.
+  (`r352828 <https://reviews.llvm.org/rL352828>`_)
+
+* Symbols that are in llvm.used are no exported by default.
+  (`r353364 <https://reviews.llvm.org/rL353364>`_)
+
+* Initial support for PIC and dynamic linking has landed.
+  (`r357022 <https://reviews.llvm.org/rL357022>`_)
+
+* wasm-ld now add ``__start_``/``__stop_`` symbols for data sections.
+  (`r361236 <https://reviews.llvm.org/rL361236>`_)
+
+* wasm-ld now doesn't report an error on archives without a symbol index.
+  (`r364338 <https://reviews.llvm.org/rL364338>`_)
+
+* The following flags have been added:
+  ``--emit-relocs`` (`r361635 <https://reviews.llvm.org/rL361635>`_),
+  ``--wrap`` (`r361639 <https://reviews.llvm.org/rL361639>`_),
+  ``--trace`` and ``--trace-symbol``
+  (`r353264 <https://reviews.llvm.org/rL353264>`_).
+
 
 MinGW Improvements
 ------------------
@@ -77,12 +216,18 @@ MinGW Improvements
   DWARF exception handling with libgcc and gcc's crtend.o.
 
 * lld now also handles DWARF unwind info generated by GCC, when linking
-  with libgcc
-
-* Many more GNU ld options are now supported, which e.g. allows the lld
-  MinGW frontend to be called by GCC
+  with libgcc.
 
 * PDB output can be requested without manually specifying the PDB file
   name, with the new option ``-pdb=`` with an empty value to the option.
   (The old existing syntax ``-pdb <filename>`` was more cumbersome to use
   with an empty parameter value.)
+
+* ``--no-insert-timestamp`` option is added as an alias to ``/timestamp:0``.
+  (`r353145 <https://reviews.llvm.org/rL353145>`_)
+
+* Many more GNU ld options are now supported, which e.g. allows the lld
+  MinGW frontend to be called by GCC.
+
+* The following options are added: ``--exclude-all-symbols``,
+  ``--appcontainer``, ``--emit-relocs``, ``--wrap``, ``--undefined``

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